/*
* Copyright 2015 The Netty Project
*
* The Netty Project licenses this file to you under the Apache License,
* version 2.0 (the "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*/
/*
* Copyright 2014 Twitter, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package io.netty.handler.codec.http2;
import io.netty.util.AsciiString;
import io.netty.util.internal.ConstantTimeUtils;
import io.netty.util.internal.PlatformDependent;
final class HpackUtil {
/**
* Compare two {@link CharSequence} objects without leaking timing information.
* <p>
* The {@code int} return type is intentional and is designed to allow cascading of constant time operations:
* <pre>
* String s1 = "foo";
* String s2 = "foo";
* String s3 = "foo";
* String s4 = "goo";
* boolean equals = (equalsConstantTime(s1, s2) & equalsConstantTime(s3, s4)) != 0;
* </pre>
* @param s1 the first value.
* @param s2 the second value.
* @return {@code 0} if not equal. {@code 1} if equal.
*/
static int equalsConstantTime(CharSequence s1, CharSequence s2) {
if (s1 instanceof AsciiString && s2 instanceof AsciiString) {
if (s1.length() != s2.length()) {
return 0;
}
AsciiString s1Ascii = (AsciiString) s1;
AsciiString s2Ascii = (AsciiString) s2;
return PlatformDependent.equalsConstantTime(s1Ascii.array(), s1Ascii.arrayOffset(),
s2Ascii.array(), s2Ascii.arrayOffset(), s1.length());
}
return ConstantTimeUtils.equalsConstantTime(s1, s2);
}
// Section 6.2. Literal Header Field Representation
enum IndexType {
INCREMENTAL, // Section 6.2.1. Literal Header Field with Incremental Indexing
NONE, // Section 6.2.2. Literal Header Field without Indexing
NEVER // Section 6.2.3. Literal Header Field never Indexed
}
// Appendix B: Huffman Codes
// http://tools.ietf.org/html/rfc7541#appendix-B
static final int[] HUFFMAN_CODES = {
0x1ff8,
0x7fffd8,
0xfffffe2,
0xfffffe3,
0xfffffe4,
0xfffffe5,
0xfffffe6,
0xfffffe7,
0xfffffe8,
0xffffea,
0x3ffffffc,
0xfffffe9,
0xfffffea,
0x3ffffffd,
0xfffffeb,
0xfffffec,
0xfffffed,
0xfffffee,
0xfffffef,
0xffffff0,
0xffffff1,
0xffffff2,
0x3ffffffe,
0xffffff3,
0xffffff4,
0xffffff5,
0xffffff6,
0xffffff7,
0xffffff8,
0xffffff9,
0xffffffa,
0xffffffb,
0x14,
0x3f8,
0x3f9,
0xffa,
0x1ff9,
0x15,
0xf8,
0x7fa,
0x3fa,
0x3fb,
0xf9,
0x7fb,
0xfa,
0x16,
0x17,
0x18,
0x0,
0x1,
0x2,
0x19,
0x1a,
0x1b,
0x1c,
0x1d,
0x1e,
0x1f,
0x5c,
0xfb,
0x7ffc,
0x20,
0xffb,
0x3fc,
0x1ffa,
0x21,
0x5d,
0x5e,
0x5f,
0x60,
0x61,
0x62,
0x63,
0x64,
0x65,
0x66,
0x67,
0x68,
0x69,
0x6a,
0x6b,
0x6c,
0x6d,
0x6e,
0x6f,
0x70,
0x71,
0x72,
0xfc,
0x73,
0xfd,
0x1ffb,
0x7fff0,
0x1ffc,
0x3ffc,
0x22,
0x7ffd,
0x3,
0x23,
0x4,
0x24,
0x5,
0x25,
0x26,
0x27,
0x6,
0x74,
0x75,
0x28,
0x29,
0x2a,
0x7,
0x2b,
0x76,
0x2c,
0x8,
0x9,
0x2d,
0x77,
0x78,
0x79,
0x7a,
0x7b,
0x7ffe,
0x7fc,
0x3ffd,
0x1ffd,
0xffffffc,
0xfffe6,
0x3fffd2,
0xfffe7,
0xfffe8,
0x3fffd3,
0x3fffd4,
0x3fffd5,
0x7fffd9,
0x3fffd6,
0x7fffda,
0x7fffdb,
0x7fffdc,
0x7fffdd,
0x7fffde,
0xffffeb,
0x7fffdf,
0xffffec,
0xffffed,
0x3fffd7,
0x7fffe0,
0xffffee,
0x7fffe1,
0x7fffe2,
0x7fffe3,
0x7fffe4,
0x1fffdc,
0x3fffd8,
0x7fffe5,
0x3fffd9,
0x7fffe6,
0x7fffe7,
0xffffef,
0x3fffda,
0x1fffdd,
0xfffe9,
0x3fffdb,
0x3fffdc,
0x7fffe8,
0x7fffe9,
0x1fffde,
0x7fffea,
0x3fffdd,
0x3fffde,
0xfffff0,
0x1fffdf,
0x3fffdf,
0x7fffeb,
0x7fffec,
0x1fffe0,
0x1fffe1,
0x3fffe0,
0x1fffe2,
0x7fffed,
0x3fffe1,
0x7fffee,
0x7fffef,
0xfffea,
0x3fffe2,
0x3fffe3,
0x3fffe4,
0x7ffff0,
0x3fffe5,
0x3fffe6,
0x7ffff1,
0x3ffffe0,
0x3ffffe1,
0xfffeb,
0x7fff1,
0x3fffe7,
0x7ffff2,
0x3fffe8,
0x1ffffec,
0x3ffffe2,
0x3ffffe3,
0x3ffffe4,
0x7ffffde,
0x7ffffdf,
0x3ffffe5,
0xfffff1,
0x1ffffed,
0x7fff2,
0x1fffe3,
0x3ffffe6,
0x7ffffe0,
0x7ffffe1,
0x3ffffe7,
0x7ffffe2,
0xfffff2,
0x1fffe4,
0x1fffe5,
0x3ffffe8,
0x3ffffe9,
0xffffffd,
0x7ffffe3,
0x7ffffe4,
0x7ffffe5,
0xfffec,
0xfffff3,
0xfffed,
0x1fffe6,
0x3fffe9,
0x1fffe7,
0x1fffe8,
0x7ffff3,
0x3fffea,
0x3fffeb,
0x1ffffee,
0x1ffffef,
0xfffff4,
0xfffff5,
0x3ffffea,
0x7ffff4,
0x3ffffeb,
0x7ffffe6,
0x3ffffec,
0x3ffffed,
0x7ffffe7,
0x7ffffe8,
0x7ffffe9,
0x7ffffea,
0x7ffffeb,
0xffffffe,
0x7ffffec,
0x7ffffed,
0x7ffffee,
0x7ffffef,
0x7fffff0,
0x3ffffee,
0x3fffffff // EOS
};
static final byte[] HUFFMAN_CODE_LENGTHS = {
13, 23, 28, 28, 28, 28, 28, 28, 28, 24, 30, 28, 28, 30, 28, 28,
28, 28, 28, 28, 28, 28, 30, 28, 28, 28, 28, 28, 28, 28, 28, 28,
6, 10, 10, 12, 13, 6, 8, 11, 10, 10, 8, 11, 8, 6, 6, 6,
5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 7, 8, 15, 6, 12, 10,
13, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
7, 7, 7, 7, 7, 7, 7, 7, 8, 7, 8, 13, 19, 13, 14, 6,
15, 5, 6, 5, 6, 5, 6, 6, 6, 5, 7, 7, 6, 6, 6, 5,
6, 7, 6, 5, 5, 6, 7, 7, 7, 7, 7, 15, 11, 14, 13, 28,
20, 22, 20, 20, 22, 22, 22, 23, 22, 23, 23, 23, 23, 23, 24, 23,
24, 24, 22, 23, 24, 23, 23, 23, 23, 21, 22, 23, 22, 23, 23, 24,
22, 21, 20, 22, 22, 23, 23, 21, 23, 22, 22, 24, 21, 22, 23, 23,
21, 21, 22, 21, 23, 22, 23, 23, 20, 22, 22, 22, 23, 22, 22, 23,
26, 26, 20, 19, 22, 23, 22, 25, 26, 26, 26, 27, 27, 26, 24, 25,
19, 21, 26, 27, 27, 26, 27, 24, 21, 21, 26, 26, 28, 27, 27, 27,
20, 24, 20, 21, 22, 21, 21, 23, 22, 22, 25, 25, 24, 24, 26, 23,
26, 27, 26, 26, 27, 27, 27, 27, 27, 28, 27, 27, 27, 27, 27, 26,
30 // EOS
};
static final int HUFFMAN_EOS = 256;
private HpackUtil() {
// utility class
}
}